U.S. Pat. No. 6,389,693 describes a manufacturing method comprising a step for measuring the diameter of the gas purification block, a step for measuring the mass of the retaining element, and a step for calculating the diameter of the housing as a function of the measurements done.
In certain purification members obtained using said method, one sees, in particular after a usage period of the purification member, that the exhaust gas purification block is no longer correctly retained inside the housing.
The invention aims to offset the aforementioned problem.